STORM WATER CALCULATIONS

For:

Calhoun County Pumped Wetlands

CAL883229B (North and South) Iowa Department of Agriculture and Land Stewardship

Rockwell City, Iowa

S-H PROJECT # 2142206150

January 10, 2025

I hereby certify that the portion of this engineering document was prepared by me or under my direct personal supervision. I am a duly licensed Professional Engineer under the laws of the State of Iowa.

Signature: ____________________________________________

Name: Dan Jensen, P.E. .

Date: _________________________

My license renewal date is December 31, 2026.

Pages, sheets, or divisions covered by this certification: ________ _Stormwater Report and Attachments __________________

Prepared by:

4125 Westown Parkway, Suite 100 – West Des Moines, Iowa 50266

(515) 223-8104

01/10/2025

TABLE OF CONTENTS

1. Project Summary

2. Drainage Area Map

3. Soil Map/Land Characteristics

4. Hydrology & Hydraulic Model Output

PROJECT SUMMARY

GENERAL

The proposed work includes construction of two pumped wetlands to the north of Rockwell City, IA. The location can be more specifically described as the NW ¼ of Section 29 and SW ¼ of Section 20, Township 88 North, Range 32 West of the Fifth Principal meridian, Calhoun County, Iowa. A pump system will be constructed to feed water for the wetland which is sited within an existing floodplain depression that will be excavated to provide a larger pool area. A water control structure will allow for pool elevation control and drawdown capabilities for maintenance.

DESIGN STANDARDS, ANALYSIS, AND ASSUMPTIONS

The design procedures and guidelines were obtained from the following resources:

1. “National Engineering Handbook 4 – Hydrology”

2. “NRCS Practice Standard 378 and 656” (as applicable)

DESIGN CRITERIA AND GUIDELINES

NORTH WETLAND SUMMARY

The north site consists of a 7.35-acre pool with a normal water level of 1186.0, the pool is situated in a natural floodplain depression that will be enlarged through excavation. Two pumps located on the north side of the pool will supply water to the pool from the drainage ditch and will be powered by a solar array and battery. The maximum capacity of each pump is estimated to be 1.6 CFS (3.2 CFS total) and is designed to run approximately 8 hours per day during daylight hours. Additionally, an overland flow drainage area of approximately 32.6 acres contributes runoff to the wetland pool. There is no proposed embankment for the north pool. The natural floodplain overflow is on the south side of the site at an elevation of approximately 1186.90. The pool storge at normal water level is 6.17 acre-feet.

NORTH WETLAND PRINCIPAL SPILLWAY

The principal spillway consists of a 24” CMP Riser and 18” CMP that is connected to a 48” circular CMP water control structure equipped with stop logs for water elevation control. The 48-inch-wide stop logs will be maintained approximately 1 inch below the normal water level of 1186.00 (1185.92). An 18” CMP discharge pipe will run east and daylight into Lake Creek.

NRCS 378 & NRCS 656 standards were used to design the principal spillway. A summary of the design criteria is listed below.

NRCS 378, Table 2:

Principal Spillway Capacity - 5-year, 24-hour storm o For embankments between 0 and 20 feet height, drainage areas between 20 and 80 acres, and less than 50 acre-feet of storage.

NRCS 656:

Principal Spillway Capacity - 25-year, 24-hour storm without overtopping embankment, refers to NRCS 378 for all other spillway requirements.

Based on NRCS 378, the spillway design storm shall be the 5-year, 24-hour storm. This equates to a storm producing a rainfall depth of 3.70” and shall be passed by the principal spillway without use of the auxiliary spillway. In this design the auxiliary spillway is a natural floodplain overflow with an elevation of

1186.90. The 5-year, 24-hour storm will produce a peak water surface elevation of 1186.81’.

NORTH WETLAND FREEBOARD DESIGN

The auxiliary spillway consists of an existing overflow into the drainage ditch on the south side of the wetland. The overflow is approximately 270 feet wide. Based on NRCS 378, the auxiliary spillway should pass the 25-year, 24 hours storm with 1 foot of freeboard from the top of dam. This equates to a storm producing a rainfall depth of 5.60”.

Since this site does not have a typical dam, existing topography was reviewed. The natural ground varies around the perimeter of the pool but is generally higher than 1187.0. The high-water elevation produced by the 25-year storm is 1186.97 and will be contained within the single overflow location on the south side of the pool. Furthermore, the 100-year storm produced a high-water elevation of 1187.09.

This storm may overflow in other locations at the natural floodplain drain locations.

The freeboard criteria is not practical for this application as a dam within the floodway would require a no-rise condition that may not be permittable with the Iowa DNR. A variance request for NRCS should be prepared to waive the freeboard requirement for this site.

SOUTH WETLAND

The south site consists of a 4.65-acre pool with a normal water level of 1186.0, the pool is situated in a natural floodplain depression. One pump located on the northwest side of the pool will supply water to the pool from the drainage ditch and will be powered by a solar array and battery. The maximum capacity of each pump is estimated to be 1.7 CFS. Additionally, an overland flow drainage area of approximately 9.8 acres contributes runoff to the wetland pool. A berm approximately 2 feet in height is proposed on the south end of the site to maintain the pool on the property and maintain the drainage capacity of the adjacent swale draining to the ditch. The berm elevation is proposed to be 1187.0 to match the adjacent topography. The natural floodplain overflow is on the south east corner of the site at an elevation of 1186.49. The pool storge at normal water level is 2.71 acre-feet.

SOUTH WETLAND PRINCIPAL SPILLWAY

The principal spillway consists of a 24” CMP Riser and 18” CMP that is connected to a 48” circular CMP water control structure equipped with stop logs for water elevation control. The 48-inch-wide stop logs will be maintained approximately 1 inch below the normal water level of 1186.00 (1185.92). An 18” CMP discharge pipe will run east and daylight into the existing Lake Creek.

NRCS 378 & NRCS 656 standards were used to design the principal spillway. A summary of the design criteria is listed below.

NRCS 378 Table 2:

Principal Spillway Capacity – None specified o For embankments between 0 and 20 feet height, drainage areas less than 20 acres, and less than 50 acre-feet of storage.

NRCS 656:

Principal Spillway Capacity - 25-year, 24-hour storm without overtopping embankment, refers to NRCS 378 for all other spillway requirements.

To be conservative, it was determined that passage of the 2-year 24-hour storm would be used for the principal spillway design storm. This equates to a storm producing a rainfall depth of 3.00” and shall be passed by the principal spillway without use of the auxiliary spillway. In this design the auxiliary spillway is a natural floodplain overflow with an elevation of 1186.49’. The 2-year, 24-hour storm will produce a peak water surface elevation of 1186.33.

SOUTH WETLAND FREEBOARD DESIGN

The auxiliary spillway consists of three existing overflow locations that into the drainage ditch on the south side of the wetland. Based on NRCS 378, the auxiliary spillway should pass the 25-year, 24 hours storm with 1 foot of freeboard from the top of dam. This equates to a storm producing a rainfall depth of 5.60”. The natural ground varies around the perimeter of the pool but is generally higher than 1187.0.

The high-water elevation produces by the 25-year storm was 1186.56 and is contained within two of the three overflow locations. Furthermore, the 100-year storm produced a high-water elevation of 1186.71.

This storm may overflow in other locations at the natural floodplain drain locations.

The freeboard criteria is not practical for this application as a dam within the floodway would require a no-rise condition that may not be permittable with the Iowa DNR. A variance request for NRCS should be prepared to waive the freeboard requirement for this site.

WATER QUALITY IMPROVEMENT

The wetlands drawdown was designed to meet NRCS 656 requirements. Wetlands will drawdown and return to design operating levels within 48 hours after a 10-year, 24-hour storm. To promote emergent vegetation, 50% of the pool area (98% for south wetland design and 99% for north design) shall have depths from 0-24 inches.

SLOPE DESIGN

Side slopes were designed to meet NRCS 656 requirements which references NRCS 378. Slopes designed with a ratio of three horizontal to one vertical (3:1) or flatter.

EMBANKMENT DESIGN

Per NRCS 378, top width required for dams with total heights less than 15 feet require a minimum of 10 feet top width. A 24-foot top width was chosen for this design to balance earthwork. The embankment will be overbuilt to account for minimum settlement of 5% of the total height of the dam. This equates to a final construction elevation of 1187.10’ ([2 feet x 0.05] + 1187.00).

IMPOUNDMENT LIFE

The Impoundment life was calculated using estimated sediment delivery and NRCS standard total erosion rate estimates. The erosion rates are based on the Average Annual Soil Erosion by Water on Cropland and CRP Land, 1982, published by USDA and revised in December 2000. This indicated that the erosion rates for the area ranged from 3 to 5 tons per acre per year. Furthermore, sediment delivery was based on NRCS FOTG “Erosion & Sediment Delivery”, (Chart I: Estimated sediment delivery for landform regions).

For the north wetland, the chart indicated a sediment delivery percentage of approximately 15% for a 32.6-acre drainage area located in the Des Moines Lobe Landform. For the south wetland, the chart indicated a sediment delivery percentage of approximately 28% for a 9.8-acre drainage area located in the Des Moines Lobe Landform. Finally, the estimated sediment storage is based on the normal pool storage volume which equates to 6.17 ac-ft for the north wetland and 2.71 ac-ft for the south wetland.

Based on the assumed soil erosion rate (5 T/Ac/yr), delivery ratio, a sediment unit weight of 100 PCF, and sediment capture rate of 70% of delivered sediment, approximately 22.0 tons of sediment per year (440.1 CF) is anticipated to be retained in the north wetland and approximately 12.4 tons of sediment per year (247.0 CF) is anticipated to be retained in the south wetland. This equates to an expected impoundment life of 611 years for the north wetland and 478 years for the south wetland.

It should be noted that this accounts only for the sediment anticipated from the overflow drainage areas and does not account for sediment that may be pumped in from the drainage ditch and Lake Creek.

Sediment delivery should be monitored.

GEOTECHNICAL INVESTIGATION AND EVALUATION

A geotechnical investigation has not been completed for this project.

DRAINAGE

AREA MAP

CALHOUN COUNTY CALHOUN COUNTY

D&J LAND TRUST

CALHOUN COUNTY

WUEBKER, JOEL & MONICA

KIBURZ, KENT

KIBURZ, KENT

D&J LAND TRUST

D&J LAND TRUST

WEISS, JOHN A

WEISS, JOHN A

MAGUIRE, ALEENE A

NORTH DRAINAGE AREA

AREA = 32.6 ACRES

SOUTH DRAINAGE AREA

AREA = 9.8 ACRES

SOUTH NORMAL POOL

AREA = 4.65 ACRES

NORTH NORMAL POOL

AREA = 7.35 ACRES

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TEWARDSHIP

SOIL MAP/LAND

CHARACTERISTICS

Hydrologic Soil Group—Calhoun County, Iowa

(ASDF)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

1/10/2025

367200 367300 367400 367500 367600 367700 367800 367900

367200 367300 367400 367500 367600 367700 367800 367900

42° 24' 58'' N

6'

3' ' W

42° 24' 58'' N

6'

6' ' W

42° 24' 22'' N

6'

3' ' W

42° 24' 22'' N

6'

6' ' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 15N WGS84 0 250 500 1000 1500

Feet 0 50 100 200 300

Meters Map Scale: 1:5,410 if printed on A portrait (8.5" x 11") sheet.

Soil Map may not be valid at this scale.

MAP LEGEND MAP INFORMATION

Area of Interest (AOI) Area of Interest (AOI)

Soils Soil Rating Polygons

A

A/D

B

B/D

C

C/D

D

Not rated or not available

Soil Rating Lines A

A/D

B

B/D

C

C/D

D

Not rated or not available

Soil Rating Points A

A/D

B

B/D

C

C/D

D

Not rated or not available

Water Features Streams and Canals

Transportation Rails

Interstate Highways

US Routes

Major Roads

Local Roads

Background Aerial Photography

The soil surveys that comprise your AOI were mapped at 1:15,800.

Warning: Soil Map may not be valid at this scale.

Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale.

Please rely on the bar scale on each map sheet for map measurements.

Source of Map: Natural Resources Conservation Service Web Soil Survey URL:

Coordinate System: Web Mercator (EPSG:3857)

Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required.

This product is generated from the USDA-NRCS certified data as of the version date(s) listed below.

Soil Survey Area: Calhoun County, Iowa Survey Area Data: Version 34, Aug 29, 2024

Soil map units are labeled (as space allows) for map scales 1:50,000 or larger.

Date(s) aerial images were photographed: Sep 5, 2021—Oct 14, The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.

Hydrologic Soil Group—Calhoun County, Iowa

(ASDF)

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

1/10/2025

Hydrologic Soil Group

Map unit symbol Map unit name Rating Acres in AOI Percent of AOI

55 Nicollet clay loam, 1 to 3 percent slopes

C/D 1.2 2.0%

62E Storden loam, 10 to 22 percent slopes, moderately eroded

B 1.9 3.2%

135 Coland clay loam, 0 to 2 percent slopes, occasionally flooded

C/D 26.1 44.9%

138B Clarion loam, 2 to 6 percent slopes

C 11.0 19.0%

138C Clarion loam, 6 to 10 percent slopes

B 0.4 0.7%

138C2 Clarion loam, 6 to 10 percent slopes, moderately eroded

B 17.4 30.0%

585B Coland-Spillville complex, 2 to 5 percent slopes

C/D 0.2 0.3%

Totals for Area of Interest 58.1 100.0%

Hydrologic Soil Group—Calhoun County, Iowa ASDF

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

Description

Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms.

The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows:

Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission.

Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture.

These soils have a moderate rate of water transmission.

Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission.

Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission.

If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes.

Rating Options

Aggregation Method: Dominant Condition

Component Percent Cutoff: None Specified

Tie-break Rule: Higher

Hydrologic Soil Group—Calhoun County, Iowa ASDF

Natural Resources Conservation Service

Web Soil Survey National Cooperative Soil Survey

PONDPACK

DIAGRAM

Scenario: Post-Development 10 year

Northern Drainage Area

Western Drainage Area

Buchanan Wetland

Wetland Outlet

Wetland Outfall

Wetland Outlet Structure

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Northern Drainage Area

Western Drainage Area

Buchanan Wetland

Wetland Outlet

Wetland Outfall

Wetland Outlet Structure

Pondpack Diagram

NORTH DA

SOUTH DA

SOUTH

WETLAND

NORTH

WETLAND

NORTH

PUMP

SOUTH

PUMP

NORTH

WETLAND

OUTFALL

SOUTH

WETLAND

OUTFALL

HYDROLOGY & HYDRAULIC

MODEL OUTPUT

44Addition Summary, 2 years (Post-Development 2 year)

North Wetland Outfall

43Read Hydrograph, 100 years (Post-Development 100 year)

42Read Hydrograph, 25 years (Post-Development 25 year)

41Read Hydrograph, 5 years (Post-Development 5 year)

40Read Hydrograph, 2 years (Post-Development 2 year)

SouthPump

38Unit Hydrograph (Hydrograph Table), 100 years (Post- Development 100 year)

36Unit Hydrograph Summary, 100 years (Post-Development 100 year)

34Unit Hydrograph Summary, 25 years (Post-Development 25 year)

32Unit Hydrograph Summary, 5 years (Post-Development 5 year)

30Unit Hydrograph Summary, 2 years (Post-Development 2 year)

South DA

29Read Hydrograph, 100 years (Post-Development 100 year)

28Read Hydrograph, 25 years (Post-Development 25 year)

27Read Hydrograph, 5 years (Post-Development 5 year)

26Read Hydrograph, 2 years (Post-Development 2 year)

NorthPump

24Unit Hydrograph Summary, 100 years (Post-Development 100 year)

22Unit Hydrograph Summary, 25 years (Post-Development 25 year)

20Unit Hydrograph Summary, 5 years (Post-Development 5 year)

18Unit Hydrograph Summary, 2 years (Post-Development 2 year)

North DA

15Time of Concentration Calculations, 2 years (Post-Development 2 year)

South DA

12Time of Concentration Calculations, 2 years (Post-Development 2 year)

North DA

10Time-Depth Curve, 5 years (Post-Development 5 year)

8Time-Depth Curve, 25 years (Post-Development 25 year)

6Time-Depth Curve, 2 years (Post-Development 2 year)

4Time-Depth Curve, 100 years (Post-Development 100 year)

MSE3

1Master Network Summary

Table of Contents

South Wetland

118Outlet Input Data, 100 years (Post-Development 100 year)

112Outlet Input Data, 25 years (Post-Development 25 year)

106Outlet Input Data, 5 years (Post-Development 5 year)

100Outlet Input Data, 2 years (Post-Development 2 year)

North Wetland

97Time vs. Volume, 100 years (Post-Development 100 year)

94Time vs. Volume, 25 years (Post-Development 25 year)

91Time vs. Volume, 5 years (Post-Development 5 year)

88Time vs. Volume, 2 years (Post-Development 2 year)

South Wetland

85Time vs. Volume, 100 years (Post-Development 100 year)

82Time vs. Volume, 25 years (Post-Development 25 year)

79Time vs. Volume, 5 years (Post-Development 5 year)

76Time vs. Volume, 2 years (Post-Development 2 year)

North Wetland

73Time vs. Elevation, 100 years (Post-Development 100 year)

70Time vs. Elevation, 25 years (Post-Development 25 year)

67Time vs. Elevation, 5 years (Post-Development 5 year)

64Time vs. Elevation, 2 years (Post-Development 2 year)

South Wetland (OUT)

61Time vs. Elevation, 100 years (Post-Development 100 year)

58Time vs. Elevation, 25 years (Post-Development 25 year)

55Time vs. Elevation, 5 years (Post-Development 5 year)

52Time vs. Elevation, 2 years (Post-Development 2 year)

North Wetland (OUT)

51Addition Summary, 100 years (Post-Development 100 year)

50Addition Summary, 25 years (Post-Development 25 year)

49Addition Summary, 5 years (Post-Development 5 year)

48Addition Summary, 2 years (Post-Development 2 year)

South Wetland Outfall

47Addition Summary, 100 years (Post-Development 100 year)

46Addition Summary, 25 years (Post-Development 25 year)

45Addition Summary, 5 years (Post-Development 5 year)

145Outlet Input Data, 100 years (Post-Development 100 year)

138Outlet Input Data, 25 years (Post-Development 25 year)

131Outlet Input Data, 5 years (Post-Development 5 year)

124Outlet Input Data, 2 years (Post-Development 2 year)

CAL883229B_Stormwater Report Subsection: Master Network Summary

Catchments Summary Peak Flow

(ft³/s) Time to Peak

(hours) Hydrograph

Volume (ac-ft)

Return Event

(years)

ScenarioLabel

78.3112.1504.3382Post-Development 2 year

North DA

108.8412.1506.0505Post-Development 5 year

North DA

188.0712.15010.64325Post-Development 25 year

North DA

277.4212.15016.018100Post-Development 100 year

North DA

29.6212.1001.2982Post-Development 2 year

South DA

40.9912.1001.8115Post-Development 5 year

South DA

70.3712.1003.18625Post-Development 25 year

South DA

103.4312.1004.795100Post-Development 100 year

South DA

3.200.00012.6942Post-Development 2 year

NorthPump

3.200.00012.6945Post-Development 5 year

NorthPump

3.200.00012.69425Post-Development 25 year

NorthPump

3.200.00012.694100Post-Development 100 year

NorthPump

1.700.0006.7442Post-Development 2 year

SouthPump

1.700.0006.7445Post-Development 5 year

SouthPump

1.700.0006.74425Post-Development 25 year

SouthPump

1.700.0006.744100Post-Development 100 year

SouthPump

Node Summary Peak Flow

(ft³/s) Time to Peak

(hours) Hydrograph

Volume (ac-ft)

Return Event

(years)

ScenarioLabel

3.8421.5504.7422Post-Development 2 year

North Wetland Outfall

4.3819.9005.2925Post-Development 5 year

North Wetland Outfall

22.3212.8508.92625Post-Development 25 year

North Wetland Outfall

97.7412.40014.226100Post-Development 100 year

North Wetland Outfall

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Node Summary Peak Flow

(ft³/s) Time to Peak

(hours) Hydrograph

Volume (ac-ft)

Return Event

(years)

ScenarioLabel

2.4015.0503.1732Post-Development 2 year

South Wetland Outfall

2.8114.4503.5075Post-Development 5 year

South Wetland Outfall

4.0413.5504.42325Post-Development 25 year

South Wetland Outfall

6.6413.3505.655100Post-Development 100 year

South Wetland Outfall

Pond Summary Maximum

Pond Storage (ac-ft)

Maximum Water

Surface Elevation

(ft)

Peak Flow (ft³/s)

Time to Peak (hours)

Hydrograph Volume (ac-ft)

Return Event

(years)

ScenarioLabel

(N/A)(N/A)81.5112.15010.6852Post- Development 2 year

North Wetland (IN)

12.0631,186.683.8421.5504.7422Post- Development 2 year

North Wetland

(OUT)

(N/A)(N/A)112.0412.15012.3975Post- Development 5 year

North Wetland (IN)

13.3481,186.814.3819.9005.2925Post- Development 5 year

North Wetland

(OUT)

(N/A)(N/A)191.2712.15016.99025Post- Development 25 year

North Wetland (IN)

15.1111,186.9722.3212.8508.92625Post- Development 25 year

North Wetland

(OUT)

(N/A)(N/A)280.6212.15022.365100Post- Development 100 year

North Wetland (IN)

16.5311,187.0997.7412.40014.226100Post- Development 100 year

North Wetland

(OUT)

(N/A)(N/A)31.3212.1004.6702Post- Development 2 year

South Wetland (IN)

4.3681,186.332.4015.0503.1732Post- Development 2 year

South Wetland

(OUT)

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Pond Summary Maximum

Pond Storage (ac-ft)

Maximum Water

Surface Elevation

(ft)

Peak Flow (ft³/s)

Time to Peak (hours)

Hydrograph Volume (ac-ft)

Return Event

(years)

ScenarioLabel

(N/A)(N/A)42.6912.1005.1835Post- Development 5 year

South Wetland (IN)

4.7211,186.392.8114.4503.5075Post- Development 5 year

South Wetland

(OUT)

(N/A)(N/A)72.0712.1006.55825Post- Development 25 year

South Wetland (IN)

5.7081,186.564.0413.5504.42325Post- Development 25 year

South Wetland

(OUT)

(N/A)(N/A)105.1312.1008.167100Post- Development 100 year

South Wetland (IN)

6.7291,186.716.6413.3505.655100Post- Development 100 year

South Wetland

(OUT)

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Scenario: Post-Development 100 year Storm Event: 100 yearLabel: MSE3

Return Event: 100 yearsSubsection: Time-Depth Curve

Time-Depth Curve: 100 year

100 year Label hours0.000Start Time hours0.100Increment hours24.000End Time years100Return Event

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

0.00.00.00.00.00.000 0.00.00.00.00.00.500 0.00.00.00.00.01.000 0.10.10.10.10.01.500 0.10.10.10.10.12.000 0.10.10.10.10.12.500 0.20.10.10.10.13.000 0.20.20.20.20.23.500 0.20.20.20.20.24.000 0.30.30.30.30.24.500 0.30.30.30.30.35.000 0.40.40.40.30.35.500 0.40.40.40.40.46.000 0.50.50.50.50.46.500 0.60.50.50.50.57.000 0.60.60.60.60.67.500 0.70.70.70.70.68.000 0.80.80.70.70.78.500 0.90.90.80.80.89.000 1.01.01.00.90.99.500 1.21.11.11.11.110.000 1.41.31.31.21.210.500 1.81.71.61.61.511.000 2.92.52.22.01.911.500 5.65.45.24.83.612.000 6.16.06.05.95.812.500 6.46.46.36.36.213.000 6.66.66.56.56.513.500 6.76.76.76.66.614.000 6.96.86.86.86.814.500 6.96.96.96.96.915.000 7.07.07.07.07.015.500 7.17.17.17.07.016.000 7.17.17.17.17.116.500

Page 4 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 100 yearLabel: MSE3

Return Event: 100 yearsSubsection: Time-Depth Curve

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

7.27.27.27.27.217.000 7.37.37.27.27.217.500 7.37.37.37.37.318.000 7.47.47.47.37.318.500 7.47.47.47.47.419.000 7.57.57.47.47.419.500 7.57.57.57.57.520.000 7.57.57.57.57.520.500 7.67.67.67.57.521.000 7.67.67.67.67.621.500 7.67.67.67.67.622.000 7.67.67.67.67.622.500 7.77.77.67.67.623.000 7.77.77.77.77.723.500

(N/A)(N/A)(N/A)(N/A)7.724.000

Page 5 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Scenario: Post-Development 2 year Storm Event: 2 yearLabel: MSE3

Return Event: 2 yearsSubsection: Time-Depth Curve

Time-Depth Curve: 2 year

2 year Label hours0.000Start Time hours0.100Increment hours24.000End Time years2Return Event

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

0.00.00.00.00.00.000 0.00.00.00.00.00.500 0.00.00.00.00.01.000 0.00.00.00.00.01.500 0.00.00.00.00.02.000 0.00.00.00.00.02.500 0.10.10.10.10.03.000 0.10.10.10.10.13.500 0.10.10.10.10.14.000 0.10.10.10.10.14.500 0.10.10.10.10.15.000 0.10.10.10.10.15.500 0.20.20.20.20.26.000 0.20.20.20.20.26.500 0.20.20.20.20.27.000 0.20.20.20.20.27.500 0.30.30.30.30.38.000 0.30.30.30.30.38.500 0.30.30.30.30.39.000 0.40.40.40.40.49.500 0.50.40.40.40.410.000 0.60.50.50.50.510.500 0.70.70.60.60.611.000 1.11.00.90.80.711.500 2.22.12.01.91.412.000 2.42.42.32.32.312.500 2.52.52.52.52.413.000 2.62.62.62.62.513.500 2.62.62.62.62.614.000 2.72.72.72.72.614.500 2.72.72.72.72.715.000 2.82.72.72.72.715.500 2.82.82.82.82.816.000 2.82.82.82.82.816.500

Page 6 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 2 yearLabel: MSE3

Return Event: 2 yearsSubsection: Time-Depth Curve

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

2.82.82.82.82.817.000 2.92.82.82.82.817.500 2.92.92.92.92.918.000 2.92.92.92.92.918.500 2.92.92.92.92.919.000 2.92.92.92.92.919.500 2.92.92.92.92.920.000 3.03.03.02.92.920.500 3.03.03.03.03.021.000 3.03.03.03.03.021.500 3.03.03.03.03.022.000 3.03.03.03.03.022.500 3.03.03.03.03.023.000 3.03.03.03.03.023.500

(N/A)(N/A)(N/A)(N/A)3.024.000

Page 7 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Scenario: Post-Development 25 year Storm Event: 25 yearLabel: MSE3

Return Event: 25 yearsSubsection: Time-Depth Curve

Time-Depth Curve: 25 year

25 year Label hours0.000Start Time hours0.100Increment hours24.000End Time years25Return Event

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

0.00.00.00.00.00.000 0.00.00.00.00.00.500 0.00.00.00.00.01.000 0.00.00.00.00.01.500 0.10.10.10.10.12.000 0.10.10.10.10.12.500 0.10.10.10.10.13.000 0.10.10.10.10.13.500 0.20.20.20.20.14.000 0.20.20.20.20.24.500 0.20.20.20.20.25.000 0.30.30.30.30.25.500 0.30.30.30.30.36.000 0.40.40.30.30.36.500 0.40.40.40.40.47.000 0.50.40.40.40.47.500 0.50.50.50.50.58.000 0.60.60.50.50.58.500 0.60.60.60.60.69.000 0.70.70.70.70.79.500 0.90.80.80.80.810.000 1.01.00.90.90.910.500 1.31.31.21.11.111.000 2.11.81.61.51.411.500 4.14.03.83.52.612.000 4.54.44.34.34.212.500 4.74.64.64.64.513.000 4.84.84.84.74.713.500 4.94.94.94.84.814.000 5.05.05.04.94.914.500 5.15.05.05.05.015.000 5.15.15.15.15.115.500 5.25.25.15.15.116.000 5.25.25.25.25.216.500

Page 8 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 25 yearLabel: MSE3

Return Event: 25 yearsSubsection: Time-Depth Curve

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

5.35.25.25.25.217.000 5.35.35.35.35.317.500 5.35.35.35.35.318.000 5.45.45.45.45.318.500 5.45.45.45.45.419.000 5.45.45.45.45.419.500 5.55.55.55.55.420.000 5.55.55.55.55.520.500 5.55.55.55.55.521.000 5.55.55.55.55.521.500 5.65.55.55.55.522.000 5.65.65.65.65.622.500 5.65.65.65.65.623.000 5.65.65.65.65.623.500

(N/A)(N/A)(N/A)(N/A)5.624.000

Page 9 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Scenario: Post-Development 5 year Storm Event: 5 yearLabel: MSE3

Return Event: 5 yearsSubsection: Time-Depth Curve

Time-Depth Curve: 5 year

5 year Label hours0.000Start Time hours0.100Increment hours24.000End Time years5Return Event

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

0.00.00.00.00.00.000 0.00.00.00.00.00.500 0.00.00.00.00.01.000 0.00.00.00.00.01.500 0.00.00.00.00.02.000 0.10.10.10.00.02.500 0.10.10.10.10.13.000 0.10.10.10.10.13.500 0.10.10.10.10.14.000 0.10.10.10.10.14.500 0.20.20.10.10.15.000 0.20.20.20.20.25.500 0.20.20.20.20.26.000 0.20.20.20.20.26.500 0.30.30.30.30.27.000 0.30.30.30.30.37.500 0.30.30.30.30.38.000 0.40.40.40.40.38.500 0.40.40.40.40.49.000 0.50.50.50.50.49.500 0.60.60.50.50.510.000 0.70.70.60.60.610.500 0.90.80.80.80.711.000 1.41.21.11.00.911.500 2.72.72.52.31.712.000 3.02.92.92.92.812.500 3.13.13.13.13.013.000 3.23.23.23.23.213.500 3.33.33.33.23.214.000 3.33.33.33.33.314.500 3.43.43.43.43.415.000 3.43.43.43.43.415.500 3.53.43.43.43.416.000 3.53.53.53.53.516.500

Page 10 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 5 yearLabel: MSE3

Return Event: 5 yearsSubsection: Time-Depth Curve

CUMULATIVE RAINFALL (in) Output Time Increment = 0.100 hours

Time on left represents time for first value in each row.

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Depth (in)

Time (hours)

3.53.53.53.53.517.000 3.53.53.53.53.517.500 3.63.63.63.63.518.000 3.63.63.63.63.618.500 3.63.63.63.63.619.000 3.63.63.63.63.619.500 3.73.73.73.63.620.000 3.73.73.73.73.720.500 3.73.73.73.73.721.000 3.73.73.73.73.721.500 3.73.73.73.73.722.000 3.73.73.73.73.722.500 3.73.73.73.73.723.000 3.73.73.73.73.723.500

(N/A)(N/A)(N/A)(N/A)3.724.000

Page 11 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 2 yearLabel: North DA

Return Event: 2 yearsSubsection: Time of Concentration Calculations

Time of Concentration Results Segment #1: SCS Lag ft800.00Hydraulic Length

85.000CN

ft/ft0.044Slope ft/s1.24Average Velocity hours0.179Segment Time of Concentration

Time of Concentration (Composite) hours0.179Time of Concentration (Composite)

Page 12 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 2 yearLabel: North DA

Return Event: 2 yearsSubsection: Time of Concentration Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.5)Tc = Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

Page 14 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 2 yearLabel: South DA

Return Event: 2 yearsSubsection: Time of Concentration Calculations

Time of Concentration Results Segment #1: SCS Lag ft130.00Hydraulic Length

85.000CN

ft/ft0.036Slope ft/s0.78Average Velocity hours0.046Segment Time of Concentration

Time of Concentration (Composite) hours0.083Time of Concentration (Composite)

Page 15 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 2 yearLabel: South DA

Return Event: 2 yearsSubsection: Time of Concentration Calculations

==== SCS Lag

0.000877 * (Lf**0.8) * ((1000/CN)-9)**0.7) * (Sf**-0.5)Tc = Tc= Time of concentration, hours Lf= Flow length, feet CN= SCS Curve Number Sf= Slope, ft/ft

Where:

Page 17 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 2 yearLabel: North DA

Return Event: 2 yearsSubsection: Unit Hydrograph Summary

2 yearStorm Event years2Return Event hours24.000Duration in3.0Depth hours0.179Time of Concentration (Composite) ft²1,420,056.000Area (User Defined) hours0.024Computational Time Increment hours12.149Time to Peak (Computed) ft³/s78.31Flow (Peak, Computed) hours0.050Output Increment hours12.150Time to Flow (Peak Interpolated Output) ft³/s78.31Flow (Peak Interpolated Output)

Drainage Area

85.000SCS CN (Composite) ft²1,420,056.000Area (User Defined) in1.8Maximum Retention (Pervious) in0.4Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in1.6Cumulative Runoff Depth (Pervious) ac-ft4.338Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft4.338Volume

SCS Unit Hydrograph Parameters hours0.179Time of Concentration (Composite) hours0.024Computational Time Increment

483.432Unit Hydrograph Shape Factor

0.749K Factor 1.670Receding/Rising, Tr/Tp

Page 18 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 2 yearLabel: North DA

Return Event: 2 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s206.33Unit peak, qp hours0.119Unit peak time, Tp hours0.477Unit receding limb, Tr hours0.597Total unit time, Tb

Page 19 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 5 yearLabel: North DA

Return Event: 5 yearsSubsection: Unit Hydrograph Summary

5 yearStorm Event years5Return Event hours24.000Duration in3.7Depth hours0.179Time of Concentration (Composite) ft²1,420,056.000Area (User Defined) hours0.024Computational Time Increment hours12.149Time to Peak (Computed) ft³/s108.85Flow (Peak, Computed) hours0.050Output Increment hours12.150Time to Flow (Peak Interpolated Output) ft³/s108.84Flow (Peak Interpolated Output)

Drainage Area

85.000SCS CN (Composite) ft²1,420,056.000Area (User Defined) in1.8Maximum Retention (Pervious) in0.4Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in2.2Cumulative Runoff Depth (Pervious) ac-ft6.050Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft6.050Volume

SCS Unit Hydrograph Parameters hours0.179Time of Concentration (Composite) hours0.024Computational Time Increment

483.432Unit Hydrograph Shape Factor

0.749K Factor 1.670Receding/Rising, Tr/Tp

Page 20 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 5 yearLabel: North DA

Return Event: 5 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s206.33Unit peak, qp hours0.119Unit peak time, Tp hours0.477Unit receding limb, Tr hours0.597Total unit time, Tb

Page 21 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 25 yearLabel: North DA

Return Event: 25 yearsSubsection: Unit Hydrograph Summary

25 yearStorm Event years25Return Event hours24.000Duration in5.6Depth hours0.179Time of Concentration (Composite) ft²1,420,056.000Area (User Defined) hours0.024Computational Time Increment hours12.149Time to Peak (Computed) ft³/s188.12Flow (Peak, Computed) hours0.050Output Increment hours12.150Time to Flow (Peak Interpolated Output) ft³/s188.07Flow (Peak Interpolated Output)

Drainage Area

85.000SCS CN (Composite) ft²1,420,056.000Area (User Defined) in1.8Maximum Retention (Pervious) in0.4Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in3.9Cumulative Runoff Depth (Pervious) ac-ft10.642Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft10.643Volume

SCS Unit Hydrograph Parameters hours0.179Time of Concentration (Composite) hours0.024Computational Time Increment

483.432Unit Hydrograph Shape Factor

0.749K Factor 1.670Receding/Rising, Tr/Tp

Page 22 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 25 yearLabel: North DA

Return Event: 25 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s206.33Unit peak, qp hours0.119Unit peak time, Tp hours0.477Unit receding limb, Tr hours0.597Total unit time, Tb

Page 23 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 100 yearLabel: North DA

Return Event: 100 yearsSubsection: Unit Hydrograph Summary

100 yearStorm Event years100Return Event hours24.000Duration in7.7Depth hours0.179Time of Concentration (Composite) ft²1,420,056.000Area (User Defined) hours0.024Computational Time Increment hours12.149Time to Peak (Computed) ft³/s277.52Flow (Peak, Computed) hours0.050Output Increment hours12.150Time to Flow (Peak Interpolated Output) ft³/s277.42Flow (Peak Interpolated Output)

Drainage Area

85.000SCS CN (Composite) ft²1,420,056.000Area (User Defined) in1.8Maximum Retention (Pervious) in0.4Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in5.9Cumulative Runoff Depth (Pervious) ac-ft16.015Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft16.018Volume

SCS Unit Hydrograph Parameters hours0.179Time of Concentration (Composite) hours0.024Computational Time Increment

483.432Unit Hydrograph Shape Factor

0.749K Factor 1.670Receding/Rising, Tr/Tp

Page 24 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 100 yearLabel: North DA

Return Event: 100 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s206.33Unit peak, qp hours0.119Unit peak time, Tp hours0.477Unit receding limb, Tr hours0.597Total unit time, Tb

Page 25 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 2 yearLabel: NorthPump

Return Event: 2 yearsSubsection: Read Hydrograph ft³/s3.20Peak Discharge hours15.000Time to Peak ac-ft12.694Hydrograph Volume

HYDROGRAPH ORDINATES (ft³/s) Output Time Increment = 1.000 hours

Time on left represents time for first value in each row.

Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Time

(hours) 3.203.203.203.203.200.000 3.203.203.203.203.205.000 3.203.203.203.203.2010.000 3.203.203.203.203.2015.000 3.203.203.203.203.2020.000 3.203.203.203.203.2025.000 3.203.203.203.203.2030.000 3.203.203.203.203.2035.000 3.203.203.203.203.2040.000

(N/A)3.203.203.203.2045.000

Page 26 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 5 yearLabel: NorthPump

Return Event: 5 yearsSubsection: Read Hydrograph ft³/s3.20Peak Discharge hours15.000Time to Peak ac-ft12.694Hydrograph Volume

HYDROGRAPH ORDINATES (ft³/s) Output Time Increment = 1.000 hours

Time on left represents time for first value in each row.

Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Time

(hours) 3.203.203.203.203.200.000 3.203.203.203.203.205.000 3.203.203.203.203.2010.000 3.203.203.203.203.2015.000 3.203.203.203.203.2020.000 3.203.203.203.203.2025.000 3.203.203.203.203.2030.000 3.203.203.203.203.2035.000 3.203.203.203.203.2040.000

(N/A)3.203.203.203.2045.000

Page 27 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 25 yearLabel: NorthPump

Return Event: 25 yearsSubsection: Read Hydrograph ft³/s3.20Peak Discharge hours15.000Time to Peak ac-ft12.694Hydrograph Volume

HYDROGRAPH ORDINATES (ft³/s) Output Time Increment = 1.000 hours

Time on left represents time for first value in each row.

Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Time

(hours) 3.203.203.203.203.200.000 3.203.203.203.203.205.000 3.203.203.203.203.2010.000 3.203.203.203.203.2015.000 3.203.203.203.203.2020.000 3.203.203.203.203.2025.000 3.203.203.203.203.2030.000 3.203.203.203.203.2035.000 3.203.203.203.203.2040.000

(N/A)3.203.203.203.2045.000

Page 28 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 100 yearLabel: NorthPump

Return Event: 100 yearsSubsection: Read Hydrograph ft³/s3.20Peak Discharge hours15.000Time to Peak ac-ft12.694Hydrograph Volume

HYDROGRAPH ORDINATES (ft³/s) Output Time Increment = 1.000 hours

Time on left represents time for first value in each row.

Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Flow

(ft³/s) Time

(hours) 3.203.203.203.203.200.000 3.203.203.203.203.205.000 3.203.203.203.203.2010.000 3.203.203.203.203.2015.000 3.203.203.203.203.2020.000 3.203.203.203.203.2025.000 3.203.203.203.203.2030.000 3.203.203.203.203.2035.000 3.203.203.203.203.2040.000

(N/A)3.203.203.203.2045.000

Page 29 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 2 yearLabel: South DA

Return Event: 2 yearsSubsection: Unit Hydrograph Summary

2 yearStorm Event years2Return Event hours24.000Duration in3.0Depth hours0.083Time of Concentration (Composite) ft²425,258.400Area (User Defined) hours0.011Computational Time Increment hours12.111Time to Peak (Computed) ft³/s30.36Flow (Peak, Computed) hours0.050Output Increment hours12.100Time to Flow (Peak Interpolated Output) ft³/s29.62Flow (Peak Interpolated Output)

Drainage Area

85.000SCS CN (Composite) ft²425,258.400Area (User Defined) in1.8Maximum Retention (Pervious) in0.4Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in1.6Cumulative Runoff Depth (Pervious) ac-ft1.299Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft1.298Volume

SCS Unit Hydrograph Parameters hours0.083Time of Concentration (Composite) hours0.011Computational Time Increment

483.432Unit Hydrograph Shape Factor

0.749K Factor 1.670Receding/Rising, Tr/Tp

Page 30 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 2 yearLabel: South DA

Return Event: 2 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s132.74Unit peak, qp hours0.056Unit peak time, Tp hours0.222Unit receding limb, Tr hours0.278Total unit time, Tb

Page 31 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 5 yearLabel: South DA

Return Event: 5 yearsSubsection: Unit Hydrograph Summary

5 yearStorm Event years5Return Event hours24.000Duration in3.7Depth hours0.083Time of Concentration (Composite) ft²425,258.400Area (User Defined) hours0.011Computational Time Increment hours12.111Time to Peak (Computed) ft³/s41.87Flow (Peak, Computed) hours0.050Output Increment hours12.100Time to Flow (Peak Interpolated Output) ft³/s40.99Flow (Peak Interpolated Output)

Drainage Area

85.000SCS CN (Composite) ft²425,258.400Area (User Defined) in1.8Maximum Retention (Pervious) in0.4Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in2.2Cumulative Runoff Depth (Pervious) ac-ft1.812Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft1.811Volume

SCS Unit Hydrograph Parameters hours0.083Time of Concentration (Composite) hours0.011Computational Time Increment

483.432Unit Hydrograph Shape Factor

0.749K Factor 1.670Receding/Rising, Tr/Tp

Page 32 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 5 yearLabel: South DA

Return Event: 5 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s132.74Unit peak, qp hours0.056Unit peak time, Tp hours0.222Unit receding limb, Tr hours0.278Total unit time, Tb

Page 33 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 25 yearLabel: South DA

Return Event: 25 yearsSubsection: Unit Hydrograph Summary

25 yearStorm Event years25Return Event hours24.000Duration in5.6Depth hours0.083Time of Concentration (Composite) ft²425,258.400Area (User Defined) hours0.011Computational Time Increment hours12.111Time to Peak (Computed) ft³/s71.56Flow (Peak, Computed) hours0.050Output Increment hours12.100Time to Flow (Peak Interpolated Output) ft³/s70.37Flow (Peak Interpolated Output)

Drainage Area

85.000SCS CN (Composite) ft²425,258.400Area (User Defined) in1.8Maximum Retention (Pervious) in0.4Maximum Retention (Pervious, 20 percent)

Cumulative Runoff in3.9Cumulative Runoff Depth (Pervious) ac-ft3.187Runoff Volume (Pervious)

Hydrograph Volume (Area under Hydrograph curve) ac-ft3.186Volume

SCS Unit Hydrograph Parameters hours0.083Time of Concentration (Composite) hours0.011Computational Time Increment

483.432Unit Hydrograph Shape Factor

0.749K Factor 1.670Receding/Rising, Tr/Tp

Page 34 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 25 yearLabel: South DA

Return Event: 25 yearsSubsection: Unit Hydrograph Summary

SCS Unit Hydrograph Parameters ft³/s132.74Unit peak, qp hours0.056Unit peak time, Tp hours0.222Unit receding limb, Tr hours0.278Total unit time, Tb

Page 35 of 15427 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666

1/10/2025

PondPack CONNECT Edition [10.02.00.01]

Bentley Systems, Inc. Haestad Methods Solution Center

Storm Event: 100 yearLabel: South DA

Return Event: 100 yearsSubsection: Unit Hydrograph Summary

100 yearStorm Event years100Return Event hours24.000Duration in7.7Depth hours0.083Time of Concentration (Composite) ft²425,258.400Area (User Defined) hours0.011Computational Time Increment hours12.111Time to Peak (Computed) ft³/s104.92Flow (Peak, Computed) hours0.050Output Increment hours12.100Time to Flow (Peak Interpolated Output)…